A handout photo obtained on August 21, 2017 from the Royal Society shows a life restoration of Inermorostrum xenops dolphins

But Inermorostrum xenops (I. xenops) - which translates to "defenseless snout" - had absolutely no teeth, and a set of whiskers around its jaw.
Robert Boessenecker from the College of Charleston's findings, published in Proceedings of the Royal Society B on Tuesday, claims that the newly discovered species belongs to a family of ancient dolphins related to early whales.

With only a fossilised cranium - found in a river near Charleston, South Carolina - to work with, Boessenecker and his team were able to reconstruct the snub-nosed mammal's evolution, describe its facial features and figure out what it snacked on.

At just over three feet from snout to tail, I. xenops was half the size of the common bottlenose dolphin.

The pint-size Flipper was an early offshoot from one of the two main groups of cetaceans called Odontoceti, or "toothed whale", that includes sperm whales and orca.

Like the dolphins we are familiar with oday, this group could echolocate - a form of communication using a bio sonar.

The other branch, baleen whales, are filter feeders that strain huge volumes of ocean water to net tiny, shrimp-like krill or plankton - think humpback or the gargantuan blue.

"Inermorostrum took only four million years to evolve from ancestral whales with precisely occluding teeth into a toothless, suction feeding specialist," explained Robert Boessenecker, a professor at the College of Charleston and lead author of a study in the British Royal Society journal Proceedings B.

During those four million years I. xenops lost its pearly whites, saw its snout and mouth shrink and developed super muscular lips.

"This last feature is perhaps the most critical," said Boessenecker, who deduced the dolphin's powerful smackers from a series of deep artery channels clearly designed to nourish extensive soft tissue.

"Short snouts typically occur in Odontoceti that are adept at suction feeding - the smaller the oral opening, the greater the suction," he said in a statement.

Its diet would have consisted exclusively of small fish, squid and other soft-bodied creatures. Because its nose was bent downward, the researchers suspect it prowled the ocean floor in search of prey.

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